KEMRI-Led Study Confirms Ivermectin’s Potential in Reducing Malaria Transmission by 26 percent.

A major breakthrough in the fight against malaria has been achieved through a collaborative study led by the Institute in partnership with the Barcelona Institute for Global Health (ISGlobal) and the Manhiça Health Research Center (CISM). The study released this Wednesday, 24^th, July 2025, has revealed that administering the antiparasitic drug ivermectin through Mass Drug Administration (MDA) can significantly reduce malaria transmission.

Published in the New England Journal of Medicine, the study presents compelling evidence that ivermectin, when given to populations in malaria-endemic regions, can complement existing malaria control strategies by reducing new infections by up to 26 percent. The research is part of the Broad One Health Endectocide-based Malaria Intervention in Africa (BOHEMIA) trial — the largest of its kind — coordinated by ISGlobal and funded by Unitaid.

Conducted in Kenya’s Kwale County and Mozambique’s Mopeia District, the study involved over 20,000 participants and administered more than 56,000 treatments. In Kwale, children aged 5 to 15 received a single dose of ivermectin (400 mcg/kg) for three consecutive months during the rainy season. The results showed a statistically significant drop in malaria infections, particularly in areas with high treatment coverage.

“We are pleased to have participated in this landmark study, which complements existing malaria prevention strategies,” said Ag. Director General, Prof. Elijah Songok. “Ivermectin, already effective against several parasitic infections, now shows great promise in combating malaria and other neglected tropical diseases.”

Despite ongoing efforts, malaria remains a global health threat, with an estimated 263 million cases and 597,000 deaths recorded in 2023. The efficacy of conventional vector control methods—such as insecticide-treated nets and indoor residual spraying—has waned due to increasing mosquito resistance and behavioural shifts in mosquito populations.

Ivermectin, traditionally used to treat parasitic conditions such as onchocerciasis and lymphatic filariasis, works by killing mosquitoes that feed on treated individuals. This unique mechanism offers a new avenue for vector control, particularly in regions where conventional approaches are less effective.

“The findings suggest that ivermectin MDA could be a valuable complementary strategy for malaria control, particularly in areas where mosquito resistance to insecticides is a growing concern,” noted Marta Maia, BOHEMIA’s lead entomologist from the University of Oxford.

One of the lead study researchers from the Kilifi-based KEMRI station, Dr. Joseph Mwangangi said, “These results align with the World Health Organization’s (WHO) criteria for new vector control tools.”

The study also reported an excellent safety profile for ivermectin, with only mild and short-lived side effects and no serious drug-related adverse events. This reinforces the drug’s suitability for large-scale public health interventions.

In Mozambique, implementation of the trial was challenged by Cyclone Gombe and a cholera outbreak, but it underscored the importance of community involvement. “Strong community engagement is essential,” said Francisco Saúte, Director of CISM. “Trust and collaboration with local leaders and health ministries were key to the success of the intervention.”

Beyond its impact on malaria, the MDA with ivermectin produced unexpected public health benefits. In Mozambique, the intervention led to reductions in skin infestations such as scabies and head lice. In Kenya, community members reported a notable decrease in bed bug populations.

“We are thrilled with these results,” said Carlos Chaccour, Co-Principal Investigator of BOHEMIA. “Ivermectin has demonstrated great promise and could become a pivotal tool in malaria control and elimination.”

The World Health Organization’s Vector Control Advisory Group has reviewed the results and recommended further research. Health authorities in Kenya and Mozambique are now evaluating the findings to determine whether ivermectin should be incorporated into national malaria control programmes.

“This research has the potential to reshape malaria prevention, particularly in regions where existing tools are no longer sufficient,” concluded Regina Rabinovich, Principal Investigator of BOHEMIA and Director of ISGlobal’s Malaria Elimination Initiative. “Ivermectin presents a novel, safe, and scalable solution to bolster global efforts against malaria.”